Serum levels of TSH, T3, rT3, T4 and T3-resin uptake in surgical trauma.

Changes in thyroid hormone metabolism induced by surgical trauma were studied by determination of TSH, T3, rT3, T4 and T3-resin uptake before, during and after mastectomy in 20 women and cholecystectomy in 10 women. Pronounced and reciprocal changes, explained by altered peripheral T4 metabolism were found concerning T3 and rT3. The decreased T3 and increased rT3-levels approached or exceeded the limits of the reference range on the first post-operative day. A significant increase in T3-resin uptake and a decrease in serum T4 were already observed during surgery and probably was caused by a decreased protein binding capacity. An increased concentration of TSH in the serum during surgery was followed by a significant post-operative decrease, possibly due to a suppressive effect of endogenous cortisol. No obvious difference in absolute values or the pattern of change was found between the mastectomy and cholecystectomy groups, although a somewhat more pronounced and retarded alteration in rT3 was found after cholecystectomy.